In most years, there is a very specific climate pattern at the U.S. Open.
The tournament starts at the end of the dog days of August, in the lingering heat and humidity of a New York summer. By the final matches, at the end of the first full week of September, it’s a good idea to bring a light sweater or a windbreaker to the Billie Jean King National Tennis Center.
Not this year. Not even close.
A first week filled with cool, breezy afternoons and crisp nights has given way to some of the hottest days — and nights — of the summer, with conditions that have brought some of the fittest athletes in the world nearly to their knees, even when they are playing in twilight and after sunset.